1. Field of the Invention
The present invention relates to a vehicle power supply system, and particularly to a positional relation between an inverter unit for controlling a rotating electric machine mounted in an electric vehicle, a hybrid vehicle or the like and a battery, and to a vehicle power supply system which can improve a torque characteristic of the rotating electric machine.
2. Description of the Related Art
Against the backdrop of the prevention of global warming, emission reduction of CO2 has been requested.
The reduction of CO2 in a vehicle means an improvement in fuel consumption performance, and as one of solutions thereto, the development and practical application of an electric vehicle (EV) or a hybrid vehicle (HEV) has been pursued.
Here, especially, functions required for a rotating electric machine mounted in a hybrid vehicle include idling stop at the time of stop of a vehicle, energy regeneration during deceleration running, torque assistance during acceleration running, and the like, and the improvement in fuel consumption performance is enabled by realizing these.
For example, as disclosed in JP-A-7-89355, the related art has such a structure that a control unit including an inverter for driving a rotating electric machine is mounted in an engine room, and a battery is mounted in a rear compartment of a vehicle.
In the structure as stated above, there have been problems that a DC wiring line for connecting the battery and the control unit including the inverter becomes long, so that a voltage drop in the DC wiring line becomes large, and in order to obtain both a desired torque and a desired rotation speed in the rotating electric machine, there occurs such a situation eventually that a battery voltage must be made high, and a large increase in cost and an increase in weight are caused.